LONDON, England (CNN) -- The suspected al Qaeda operative now in the custody of police in London is a "senior" figure in the terror network, U.S. government officials told CNN in Washington Thursday.

They described the man known as Esa al-Hindi as a "major player who moved operational information between key components of al Qaeda."

Officials said the information flow was among three points -- Pakistan, Britain and the United States.

Al-Hindi is believed to have been on the ground in the New York area in early 2001 conducting reconnaissance of financial buildings identified Sunday as possible attack targets, law enforcement sources told CNN Thursday.

One source said law enforcement officials have definitively placed him in three of the buildings that were cased -- the New York Stock Exchange and the Citigroup building in New York City and the Prudential Financial building in Newark, New Jersey.

Al-Hindi was one of a dozen suspects arrested Tuesday under provisions of Britain's 2000 Terrorism Act.

British police were granted permission Thursday to hold them until Sunday as they continue their investigation.

The request was necessary under British law, which would have required police to file charges by Thursday afternoon had no extension been granted.

Another arrest took place late Thursday when police took into custody one of its citizens after receiving an extradition request from U.S. authorities, who allege the man sought to use U.S.-based Web sites to raise funding for "acts of terrorism in Chechnya and Afghanistan."

New Scotland Yard identified the man as Babar Ahmad, 30, from the Tooting community in London.

Officers from the Anti-Terrorist Branch were searching three residential properties and one office in southwest London on behalf of U.S. authorities.

Potential targets

The U.S. officials in Washington said the dozen people arrested earlier this week could be described as a cell.

They said the United States has been particularly interested in al-Hindi for "some time" but would not elaborate as to why.

They also said Heathrow Airport was one of "several potential" targets in London uncovered as a result of recent investigations in Pakistan. That evidence included a sheaf of photos of potential targets.

The men were described as being between the ages of 19 and 32 and were suspected of being involved "in the commission, preparation and instigation of acts of terrorism," the statement said.

Scotland Yard said two of the men were arrested in Blackburn, Lancashire; one in Watford, Hertfordshire; one in Luton, Bedfordshire; five in Willesden, North London, including one later released; one in Wembley, North London; one in Sudbury, North London; and two in Paddington, London.

Pakistani authorities said the British raids came after it shared intelligence it gathered on links to the al Qaeda terrorist network.

British police have declined to comment on reports of a connection between the arrests and information received from Pakistani intelligence, but senior Pakistani intelligence officials said a link did exist.

They said during an interrogation of Naeem Noor Khan -- described as an al Qaeda computer expert -- he told them there was a terror network in Britain and he frequently relayed messages from Pakistan to its leader, an important al Qaeda operative.